The invention relates to a device for transmitting a force, in particular a compression force, along an essentially straight path with at least one oblong, articulated transfer element which can bend on one side.
In known devices of this type, the oblong, articulated transfer element which can bend on one side is provided by a link chain similar to a bicycle chain, which has intermediate links to allow bowing out in only one direction. The intermediate links are made and arranged in such a way that when the link chain is aimed straight and is under the influence of a compression force they lie against one another in order to transfer this compression force from a drive element, for example, a motor, to an object which the motor is supposed to act upon, for example a hinged window or a shutter. The link chain has the advantage over a rigid, oblong transfer element, namely a rod or a bar, that it can be bent and rolled up, if necessary, to save space. However, it is felt to be disadvantageous that the link chain makes noise when it moves and that it wears, which can be eliminated by caring for the link chain, but basically limits its service life. In addition, its manufacture is complicated, namely the production and attachment of the intermediate links onto the link chain.
A variant of this known device, which also belongs to the state of the art known from practice, has two link chains with intermediate elements which are brought together like a zipper at the beginning of a straight path in such a way that the intermediate links alternately mesh and wedge together. The two link chains connected with one another in this way are especially suitable for transmitting compression forces, without any undesired bowing out.
On the other hand, the two link chains can be separated from one another at the beginning of the straight path, by turning each of the two link chains around a chain wheel and pulling the two link chains apart at the gap which is formed between the two chain wheels. Here the intermediate links put on the link chains must be made to function the way a zipper connects and separates. Despite its improved properties for transmitting compression force, this device with two link chains has essentially the same disadvantages as the known device with only one link chain which was explained at the beginning.
By contrast, this invention is based on the task of developing a device of the type mentioned at the beginning for transmitting a force, in particular a compression force, along an essentially straight path, such that the transfer element experiences little wear and makes little noise and also is not complicated to manufacture.
This task is solved in a device of the type mentioned at the beginning.
The toothed belt provided as a transfer element makes it possible to transfer compression force on a straight path and to turn outside the straight path in a manner which produces little noise and experiences little wear. Moreover, the block-like elevations on its back side, which transfer the compression force by lying against one another and supporting one another, can be made as a single piece from the toothed belt directly during its manufacture. Thus, it does away with separate manufacturing processes to produce intermediate links and attach them, as is required for link chains. Moreover, the normal toothed belt which is modified in this simple way is thicker than a normal toothed belt, due to the shape on its back side, so it can function especially reliably.
The device which is especially useful, is characterized by the fact that the block-like elevations on the back side of the toothed belt are formed by slits arranged as indicated. Adding the slits represents only a slight modification of the normal manufacture of the toothed belt.
The further development has an approximately cylindrical recess made at the foot of every slit in the back side of the toothed belt with the slit running transversely to the longitudinal direction of the toothed belt. This recess largely avoids notch effect, which would diminish the mechanical strength of the toothed belt
An especially advantageous variant of the device with two oblong, articulated transfer elements which can bend on one side and which are brought together like a zipper along an essentially straight path, has a longitudinal, articulated transfer element which can bend on one side in the form of two toothed belts, each of which has teeth on one side and whose back side, which is turned away from the toothed side, has, in the longitudinal direction of the toothed belt, a series of wedge-shaped elevations arranged with gaps between them so that on the straight path the elevations of the two toothed belts are capable of meshing with one another in alternation, like a zipper. This device with two toothed belts forming a single unit in the straight path section is especially suitable for securely transmitting compression forces, since the two toothed belts which interlock like a zipper cannot easily deviate to one side. Moreover, here bringing the toothed belts together into a zipper-like connection, but also the opposite motion sequence of separating them, produces especially little noise. This device is also characterized by the fact that it is simple to manufacture, for the reasons mentioned above.
In particular, in the last-mentioned variant of the device with two toothed belts, the wedge-shaped elevation is shaped, if the toothed belt is viewed from the side, so that it gradually changes from a narrow foot section into the back side of the toothed belt, widening outward from the foot section symmetrically to an axis of symmetry which runs at right angles to the longitudinal direction of the toothed belt On the outside, the wedge-shaped elevation is terminated by a head section which has roughly the shape of a cuboid. This shape of the wedge-shaped elevation makes possible, on the one hand, low-friction, zipper-like interlocking of the two toothed belts and their separation, and on the other hand, secure transfer of the compression force when the two toothed belts are connected.
It is advantageous for the flanks of the wedge-shaped elevations to be rounded off in the area which widens to make the zipper-like connection and separation of the two toothed belts especially low-friction.
The device can be completed by a sprocket, with the toothed belt being turned between the straight path, through which the compression force is transferred, and another path, which leads to the storage place of the toothed belt section which is unnecessary for transferring the pressure.
To complete the device for transmitting a compression force, it can have the feature that the toothed belt is turned on a sprocket. Turning the toothed belt creates a spatial arrangement which saves space. In addition, the sprocket can have a partially bent guide channel for the toothed belt arranged on it which covers the toothed belt over a partial circumference of the sprocket. This guide channel ensures that the toothed belt does not jump off the sprocket, but rather transfers the force exerted on it by the sprocket as a compression force through the straight path.
The embodiment of the device with two toothed belts which are brought together like a zipper along an essentially straight path has a guide channel arrangement which is symmetrical to the straight path, with one sprocket for each toothed belt and one section of the guide channel partially covering each sprocket on the outside. A common straight section of the guide channel is arranged as an extension of the gap between the sprockets. In this respect, this arrangement of the guide channel fulfills the same advantageous function as illustrated further above for an individual sprocket. Moreover, here the two sections of the guide channel which partially cover the sprocket run together in a wedge shape in extension of the gap on the side turned away from the straight section of the guide channel, and form in this place a separation point for the two toothed belts.
The arrangement of the guide channel for two sprockets can be designed in an especially a compact manner as a subassembly or even as a single unit by making the sections of the guide channel to be components of a guide channel part.
In an alternative device for transmitting a compression force, the transfer element consists of sections of an extrusion which has teeth on a contact side to engage into a sprocket mounted so that it can rotate, which has flat support surfaces oriented essentially at right angles to the contact side, with the support surfaces of several of these sections of the extrusion being arranged essentially next to one another and with these sections having means which are capable of holding these sections together in the longitudinal direction of the transfer element in such a way that they can bow out essentially on one side about a virtual transverse axis.
It is not complicated to manufacture this transfer element even for small production runs. This is especially true if the sections are sawed from an aluminum extrusion. In the longitudinal direction of the extrusion whose cross section is essentially rectangular, the support surfaces of the sections are performed on two external sides turned away from one another, so that the size of the support surfaces of the separated or sawed off sections is obtained in a simple manner from the longitudinal distances between the separation points of the extrusion. Thus, the size of the support surfaces can be adjusted in a flexible manner to the forces to be transferred through the support surfaces, and this is easy to accomplish, without additional tools. This makes it possible to produce even large support surfaces very simply, which exert small surface pressures. It is not necessary to use a material which has especially great strength, which in turn makes it easier on the separation and processing tool.
A first possibility of forming the means of holding these sections together in the longitudinal direction in such a way that they can bend out essentially on one side is by shaping the sections, or the extrusion from which they are cut to length. Here the link cylinder on one end of a section and the link socket partially By encompassing it on the end of an immediately neighboring section form a pivoting link which can pivot sufficiently so that the transfer element can turn, typically about 90xc2x0. The link socket and the link cylinder are performed on two edges of the extrusion which are turned away from one another, so after the sections are separated from the extrusion they do not need to be shaped.
In a further development, these sections, which are put together into the transfer element, can be prevented from coming apart on the side by passing a bolt through a hole which goes through the transfer element in the transverse direction and which also covers the link socket partially encompassing this ink cylinder on the side.
A usually simpler alternative embodiment of the means of holding these sections together in the longitudinal direction in such a way that they can bend out essentially on one side, which comprises at least one hole going through each section at right angles to the support surfaces, that is in the longitudinal direction of the transfer element and parallel to and near the contact side of the section, which hardly affects its ability to bend out in essentially one direction. The specific means are completed by at least one oblong, flexibly bending connection element which passes through the holes going through the sections lying essentially next to one another. It is expedient for this connection element to be a wire cord.
It is preferable for the first end of the flexibly bending connection element or steel cord to be connected with an extreme section of the transfer element, and for its second end to be held under tension by a spring near an opposite extreme section of the transfer element.
The latter safety measure is especially useful outside a housing in which especially the sprocket(s) is (are) mounted so it (they) can rotate. Inside the housing, by contrast, it is sufficient to have two parallel, flat guide surfaces between which the transfer element is guided.
In a simplest embodiment the sections separated from the extrusion are approximately cuboid. Their contact sides are capable of engaging in a sprocket and cam transfer considerable compression forces, e.g. to a window, over a straight path of the simple transfer element or strand which they form, without bowing out
However, bowing out to the side on the straight path can be prevented to a much greater extent by two transfer elements, which themselves can bend on one side, which are made from sections of an extrusion described above, and which are put together like a zipper. This is accomplished by the design of the sections, each of which has a flat, cuboid-shaped foot section, on the outside of which are support surfaces turned away from one another and a wedge-shaped elevation projecting from them at right angles. Such elevations which lie opposite one another and mesh together are capable of interlocking with one another like a zipper. This should not be confused with the interlocking of the sprockets, which are in contact with the contact side of the sections and which are preferably, but not exclusively, designed as a mangle gear